Tech Log Entry: Joining a Domain in Linux

Overview

This log outlines the steps taken to join a CentOS machine to a Windows Active Directory domain for centralized authentication and resource access.

Prerequisites

Before proceeding, I will become the root user temporarily to execute administrative commands. I will do this by running:

sudo -i

Installing Required Packages

I need to install the necessary packages for joining the domain. I will use the following command:

yum install realmd sssd adcli samba samba-common

Starting and Enabling SSSD

Next, I need to start and enable the System Security Services Daemon (SSSD) to ensure it runs at boot:

systemctl start sssd systemctl enable sssd

Discovering the Domain

I will use the realm command to discover the Active Directory domain. I replace [YOUR_DOMAIN] with the actual domain name:

realm discover [YOUR_DOMAIN]

Joining the Domain

I will join the domain using the following command, providing an Active Directory administrator username and password:

realm join --user=[AD_USERNAME] [YOUR_DOMAIN]

Verifying the Domain Join

After successfully joining the domain, I will verify the status with:

realm list

Configuring SSSD

If necessary, I will edit the SSSD configuration file to adjust settings:

nano /etc/sssd/sssd.conf

I will ensure the configuration file has appropriate permissions:

chmod 600 /etc/sssd/sssd.conf

Restarting the SSSD Service

To apply any changes, I will restart the SSSD service:

systemctl restart sssd

Testing Domain User Login

Finally, I will test logging in with an Active Directory user account to confirm the domain join was successful. I will do this by switching users in the terminal:

su - [AD_USERNAME]@[YOUR_DOMAIN]